This invention concerns a tool for the precise gripping and manipulation of small objects, and more particularly concerns a hand-held tool for handling the driver pins and springs of a pin tumbler lock.
In pin tumbler locks of conventional design, a plug which is a cylinder having a series of radially disposed channels is rotatably mounted within a cylindrical bore in a housing having a matching series of straight channels, known as "pin chambers", which open upon said bore and are closed at their opposite extremities, furthest from the bore. Each pin chamber is adapted to confine a coil spring in abutment with said close extremity, and a driver pin or pin tumbler which is urged toward the plug by the spring.
In the area of locksmith work, it is often found necessary to reinstall driver pins and springs that have been removed from a pin tumbler lock upon its disassembly. The fact that the pin is under pressure from the spring requires that, as each pin is forcibly restored to its proper chamber, it must immediately be held in place when the restoring force is removed. Such holding effect is achieved by a tool, known as a plug follower, which enters the bore in close-fitting sliding engagement therewith and permits displacement by said plug. Any tool for holding and installing the driver pins must therefore be compatible with the function of the plug follower, and would have enhanced value if it could smultaneously hold both the driver pin and corresponding spring.
It is the current practice in the locksmith trade to use tweezers to grip and manipulate driver pins and springs during installation and disassembly operations. Since the gripping action of the tweezers is dependent upon the force applied by the locksmith's fingers, the pins or springs may accidentally be dropped if insufficient force is applied, and the springs may be crushed if the gripping force is excessive. A constant and adequate gripping force is difficult to achieve not only because of the inconsistency of finger force but also because the compressive force applied by opposed fingers at any given site along the length of the tweezers may have varied effect at the gripping extremity of the tweezers due to flexibility in the arms of the tweezers and leverage factors.
It is accordingly an object of the present invention to provide a tool for installing the driver pins and springs into a pin tumbler lock.
It is another object of this invention to provide a tool as in the foregoing object whose gripping force is precise and adjustable.
It is a further object of the present invention to provide a tool of the aforesaid nature specially adapted to install driver pins against spring pressure.
It is a still further object of this invention to provide a tool of the aforesaid nature having the capability of simultaneously holding a driver pin and associated spring.
It is yet another object of the present invention to provide a tool of the aforesaid nature of rugged and durable construction amenable to low cost manufacture.
These objects and other objects and advantages of the invention will be apparent from the following description.